New sensor for real-time trench depth monitoring in micromachining applications

Pascal Amary; Ramdane Benferhat; Kevin J. Liddane; Alain Ostrovsky

doi:10.1117/12.361223

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30 August 1999 New sensor for real-time trench depth monitoring in micromachining applications

Pascal Amary, Ramdane Benferhat, Kevin J. Liddane, Alain Ostrovsky

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Proceedings Volume 3874, Micromachining and Microfabrication Process Technology V; (1999) https://doi.org/10.1117/12.361223
Event: Symposium on Micromachining and Microfabrication, 1999, Santa Clara, CA, United States

Abstract

A new interferometric method for trench depth monitoring in micromachining applications is presented. As compared to other interferometric techniques, this new method uses a Wollaston prism to generate two linearly polarized beams, which are recombined after reflection on the sample. This differential method, by taking advantage of the polarization properties of the light allows an accurate monitoring of the trench depth. New insights on interferometry are given, in particular it is shown that an optical model taking into account the effect of the mask evolution and its etching during the process leads to an improvement of the precision of the measurements. The application of this new interferometric method to two different processes is presented. This will show that real time Twin-Spot interferometry appears as a powerful technique for deep trench monitoring in micromachining applications.

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Pascal Amary, Ramdane Benferhat, Kevin J. Liddane, and Alain Ostrovsky "New sensor for real-time trench depth monitoring in micromachining applications", Proc. SPIE 3874, Micromachining and Microfabrication Process Technology V, (30 August 1999); https://doi.org/10.1117/12.361223

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